The correct answer to this open question is the following.
What made it possible for Eleanor of Aquitaine to be so active at the highest political levels of medieval Europe, where men dominated the political stage was the fact that she was the queen of France and an influential figure to her husband, King Henry VII. Eleanor was the daughter of a prominent rich man, so she was used to behaving in the high spheres of society since she was a child. She received the best education in that time and had refined modals.
She was a brave woman that went to the Crusades, beside her husband, the King. This created a great impression on the French people.